Blasting cartridge



June 16, J. BARAB 2,044,345

BLASTING CARTRIDGE Filed- Jan. 16, 1952 50 fore require that the userloading the hole use 'his judgment, or carry out instructions, with noPatented June 16, y1936 UNITED STATES PATENT OFFICE BLASTING CARTRIDGEApplication January 16, 1932,`Serial No. 587,007

2 Claims.

This invention relaftesto an improvement in blasting cartridges, and inmethod of blasting. More particularly, the cartridge and method inaccordance with" this invention will be found especially advantageous inconnection with the mining of coal.

Heretofore in the mining of coal, it has been customary to fire theexplosive, as a dynamite, in contact with the coal with the result thatthe coal is excessively broken or, in other words.'

an undesirable amount of nes as compared with lump are produced.According to certain practiceand as required in certain States, theexplosive is placed in a drilled hole and the hole in front of theexplosive lled with tamping or stemming material. According to suchpractice, since the explosive is in contact with the coal, the coalreceives the full force of the explosive and is undesirably shattered,especially where the explosive is a dynamite. According to anotherpractice, where permissible, the explosive is placed at the bottom ofthe hole and an air space is left between the Astemming and theexplosive. Such an air space, known as air cushioning. is provided by,for example, placing empty cartridges, or a wireV bent at both ends, asa spacer, between the explosive and the tamping.

plosive and the tamping has the eil'ect of somewhat distributing'theexplosive force and hence reducing the shattering of the coal. However,the air space as providedin this manner is prohibited in some States,and in that the explosive per se is in direct contact with the coal,which causes it to have a large shattering eiect.

Now, in accordance with this invention, there is provided a blastingcartridge and a method of blasting by which the advantages of aircushioning may be obtained,in connection with the necessary stemming andhence without any prohibition, and bywhich contact of the explosive withcoal to be Lblasted will be avoided.

In accordance with this invention there is provided a container forv-the explosive charge which will limit deflnitely the amount ofexplosives used and make it possible to use a predetermined amount ofcushioning. By employing the method of my'in'vention this can be`predetermined,

and the special cartridges made up before beginning to load the hole.All methods used heretoassurance that instructions are being followedaccurately. The importance of this point is ob?- vious when it isconsidered that to a large extent excessive shattering of coal is due tooverloading of the borehole with explosives, and that it is difficult orimpossible to get the miner to load a hole with just` the proper amountof explosive, in order to produce the maximum percentageof lump coal. y

In accordance with this invention the explosive when positioned in thehole will be spacedA from the wall of the hole inany convenient manner,an air space will be provided circumferentially about the explosive andconsequently the explosive ,will be out of /contact with the coal, thehole beyond the explosive will be lled with tamping and consequentlywill comply with State laws.

The methodembodying this invention may be carried out with any desiredform oi explosive, but will be found most useful in connection with, forexample, permissible dynamites of various types, the shattering effectof which when ired in contact with coal Vand fully tamped, or even withair tamping, is undesirable. The cartridge in accordance with thisinvention will beso constructed or combined with means whereby when itis inplace in a; hole of larger diameter than the cartridge, it will bespaced from the walls of the hole. The means for spacing the surfaces ofthe cartridge fromv the wall of the hole may be of various types and maybe a part of the cartridge or separate for assembly therewith on loadingof the cartridge into the hole.

Having now indicated in a general way the nature and purpose of myinvention, I will proceed to a more detailed description thereof withreference to the accompanying drawing in which:

Figure l shows diagrammatically a bore hole loaded with a cartridgeembodying this invention and arranged for blasting in accordance withthe method embodying this invention.'

Figures 2-5 show respectively cartridges embodying modications of thisinvention.

Figure s shows a. detail of the structure' shown' in Figure 4.

Figure '7 is an in Figure 5.

Referring more particularly to Figure 1, A indicates a seam of coalhaving a face b and undercut as at c. Near. the top of the seam a hole eis provided of larger diameter than the end view oi' the casing shownexplosive cartridge, at the inner end or bottom of which is a dynamitecartridge, or cartridges AJ. At intervals about the dynamite cartridge,which is smaller in diameter than the hole e, are placed spacingmembers, as washers g, having a central hole through which the cartridgeextends. The

spacers or washers a are of about the diameter of the hole e and serveto position the cartridge in spaced relation to the wall of the hole sothatl an air space D is provided all around the cartridge I indicatestamping or wadding material with which the hole e is filled from thecartridge out. J indicates lead wires or a fuse for firing the cap withwhich the cartridge is primed.,

On the firing of the cartridge f, which it will be noted is not incontact with the coal throughout its length, the explosive face will becushioned by the air space h surrounding the cartridge with avoidance ofundesirable shattering of the coal. At the same time, as will be noted,a blow out willy be avoided since the cartridge is fully tamped.

Referring now to Figures 2-7, in all of which f indicates a dynamitecartridge or cartridges, in Figure 2 the cartridge f is surrounded by aframe 1c the members of which, of wavy form, extend lengthwise of thecartridge and are secured to the cartridge by connecting portions k',which extend over the ends of the cartridge. The frame may be attachedtothe cartridge when it is prepared for loading and will operate toposition the cartridge in spaced relation to the walls f the bore hole.

In Figure 3 the cartridge orcartridges f are positioned within an outercasing Z and spaced from the walls thereof by means of Washers g.I'he`cartridge when loaded into a hole with the outer casing l in placewill be spaced from the walls of the hole throughout its length. Thecaslng l may be perforated as at m.

In Figure 4 the cartridge f is provided at intervals with washers g, asin Figure 1, the washers g being provided with a central hole and may beslitted radially from the hole, as shown at n, Figure 6, in order toinsure a frictionally tight fit of the washers on the cartridge.

In Figure 5 the cartridge is slipped through holes in the end members qof a carton or casing o, being spaced from the walls thereof by the endnember q and hence when loaded into the casing will be spaced from thewalls of the hole. Figure I shows an end view of the casing yp fromwhich it will be noted that the end members q thereof may Je perforatedwith holes r.

If desired the space between the surface of the cartridge and the wallof the.hole may be illled with a flame quenching material, as forexample, sodium chloride, ammonium chloride, borax, or the like. Thus,as shownin Figure 5, the casing p may be filled around the cartridgewith a flame quenching material s.

'I'he several forms of spacers described -above and various other formswhich will be within the skill of the art to devise, may be made of anydesired material as thin metal, heavy, paper or cardboard, etc. When thespacer is made of paper or cardboard, such will desirably befireproofed, as for` example, by treatment with silicate of soda,magnesium sulphate, ammonium chloride, sodium chloride, borax, etc., inorder to avoid the carrying of ame or glow into the mine atmosphereshould the spacer or portions thereof be blown into the mine anddesirably also perforated.

It will be appreciated that this invention from the broad standpointcontemplates the provision of an air space between the explosive and thewall of the. hole, however, it will be understood that the embodimentsand practical application of the invention as described herein areillustrative only, it being contemplated that various modiications instructure and procedure may be made over those described Withoutdeparting from the invention.

What I claim and desire to protect by Letters Patent is:

1. In combination, a. blasting cartridge and means for uniformly spacingthe surface of the cartridge from the wall of a bore hole of largerdiameter than the cartridge, said means comprising a cylindrical bodyadapted to enclose said cartridge and having corrugated side walls.

.2. In combination, a blasting cartridge and means for uniformly spacingthe surface of the cartridge from the Wall of a bore hole of largerdiameter than the cartridge, said means compris-l ing a cylindricalcontainer having substantially the diameter of the bore hole for saidcartridge and means for centrally positioning the cartridge in saidcontainer, the side walls of said container being perforated at aplurality of points.

JACOB BARAB

